/********************************** (C) COPYRIGHT  *******************************
* File Name          : ch32f20x_can.c
* Author             : WCH
* Version            : V1.0.0
* Date               : 2021/08/08
* Description        : This file provides all the CAN firmware functions.
* Copyright (c) 2021 Nanjing Qinheng Microelectronics Co., Ltd.
* SPDX-License-Identifier: Apache-2.0
*******************************************************************************/
#include "ch32f20x_can.h"
#include "ch32f20x_rcc.h"

/* CAN CTLR Register bits */
#define CTLR_DBF                     ((uint32_t)0x00010000)

/* CAN Mailbox Transmit Request */
#define TMIDxR_TXRQ                  ((uint32_t)0x00000001)

/* CAN FCTLR Register bits */
#define FCTLR_FINIT                  ((uint32_t)0x00000001)

/* Time out for INAK bit */
#define INAK_TIMEOUT                 ((uint32_t)0x0000FFFF)
/* Time out for SLAK bit */
#define SLAK_TIMEOUT                 ((uint32_t)0x0000FFFF)


/* Flags in TSTATR register */
#define CAN_FLAGS_TSTATR             ((uint32_t)0x08000000)
/* Flags in RFIFO1 register */
#define CAN_FLAGS_RFIFO1             ((uint32_t)0x04000000)
/* Flags in RFIFO0 register */
#define CAN_FLAGS_RFIFO0             ((uint32_t)0x02000000)
/* Flags in STATR register */
#define CAN_FLAGS_STATR              ((uint32_t)0x01000000)
/* Flags in ERRSR register */
#define CAN_FLAGS_ERRSR              ((uint32_t)0x00F00000)

/* Mailboxes definition */
#define CAN_TXMAILBOX_0              ((uint8_t)0x00)
#define CAN_TXMAILBOX_1              ((uint8_t)0x01)
#define CAN_TXMAILBOX_2              ((uint8_t)0x02)


#define CAN_MODE_MASK                ((uint32_t) 0x00000003)

static ITStatus CheckITStatus( uint32_t CAN_Reg, uint32_t It_Bit );


/*********************************************************************
 * @fn      CAN_DeInit
 *
 * @brief   Deinitializes the CAN peripheral registers to their default reset
 *        values.
 *
 * @param   CANx - where x can be 1 or 2 to select the CAN peripheral.
 *
 * @return  none
 */
void CAN_DeInit( CAN_TypeDef *CANx )
{
    if( CANx == CAN1 )
    {
        RCC_APB1PeriphResetCmd( RCC_APB1Periph_CAN1, ENABLE );
        RCC_APB1PeriphResetCmd( RCC_APB1Periph_CAN1, DISABLE );
    }
    else
    {
        RCC_APB1PeriphResetCmd( RCC_APB1Periph_CAN2, ENABLE );
        RCC_APB1PeriphResetCmd( RCC_APB1Periph_CAN2, DISABLE );
    }
}

/*********************************************************************
 * @fn      CAN_Init
 *
 * @brief   Initializes the CAN peripheral according to the specified
 *        parameters in the CAN_InitStruct.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          CAN_InitStruct - pointer to a CAN_InitTypeDef structure that
 *        contains the configuration information for the CAN peripheral.
 *
 * @return  InitStatus - CAN InitStatus state.
*             CAN_InitStatus_Failed.
*             CAN_InitStatus_Success.
 */
uint8_t CAN_Init( CAN_TypeDef *CANx, CAN_InitTypeDef *CAN_InitStruct )
{
    uint8_t InitStatus = CAN_InitStatus_Failed;
    uint32_t wait_ack = 0x00000000;

    CANx->CTLR &= ( ~( uint32_t )CAN_CTLR_SLEEP );
    CANx->CTLR |= CAN_CTLR_INRQ ;

    while( ( ( CANx->STATR & CAN_STATR_INAK ) != CAN_STATR_INAK ) && ( wait_ack != INAK_TIMEOUT ) )
    {
        wait_ack++;
    }

    if( ( CANx->STATR & CAN_STATR_INAK ) != CAN_STATR_INAK )
    {
        InitStatus = CAN_InitStatus_Failed;
    }
    else
    {
        if( CAN_InitStruct->CAN_TTCM == ENABLE )
        {
            CANx->CTLR |= CAN_CTLR_TTCM;
        }
        else
        {
            CANx->CTLR &= ~( uint32_t )CAN_CTLR_TTCM;
        }

        if( CAN_InitStruct->CAN_ABOM == ENABLE )
        {
            CANx->CTLR |= CAN_CTLR_ABOM;
        }
        else
        {
            CANx->CTLR &= ~( uint32_t )CAN_CTLR_ABOM;
        }

        if( CAN_InitStruct->CAN_AWUM == ENABLE )
        {
            CANx->CTLR |= CAN_CTLR_AWUM;
        }
        else
        {
            CANx->CTLR &= ~( uint32_t )CAN_CTLR_AWUM;
        }

        if( CAN_InitStruct->CAN_NART == ENABLE )
        {
            CANx->CTLR |= CAN_CTLR_NART;
        }
        else
        {
            CANx->CTLR &= ~( uint32_t )CAN_CTLR_NART;
        }

        if( CAN_InitStruct->CAN_RFLM == ENABLE )
        {
            CANx->CTLR |= CAN_CTLR_RFLM;
        }
        else
        {
            CANx->CTLR &= ~( uint32_t )CAN_CTLR_RFLM;
        }

        if( CAN_InitStruct->CAN_TXFP == ENABLE )
        {
            CANx->CTLR |= CAN_CTLR_TXFP;
        }
        else
        {
            CANx->CTLR &= ~( uint32_t )CAN_CTLR_TXFP;
        }

        CANx->BTIMR = ( uint32_t )( ( uint32_t )CAN_InitStruct->CAN_Mode << 30 ) | \
                      ( ( uint32_t )CAN_InitStruct->CAN_SJW << 24 ) | \
                      ( ( uint32_t )CAN_InitStruct->CAN_BS1 << 16 ) | \
                      ( ( uint32_t )CAN_InitStruct->CAN_BS2 << 20 ) | \
                      ( ( uint32_t )CAN_InitStruct->CAN_Prescaler - 1 );
        CANx->CTLR &= ~( uint32_t )CAN_CTLR_INRQ;
        wait_ack = 0;

        while( ( ( CANx->STATR & CAN_STATR_INAK ) == CAN_STATR_INAK ) && ( wait_ack != INAK_TIMEOUT ) )
        {
            wait_ack++;
        }

        if( ( CANx->STATR & CAN_STATR_INAK ) == CAN_STATR_INAK )
        {
            InitStatus = CAN_InitStatus_Failed;
        }
        else
        {
            InitStatus = CAN_InitStatus_Success ;
        }
    }

    return InitStatus;
}

/*********************************************************************
 * @fn      CAN_FilterInit
 *
 * @brief   Initializes the CAN peripheral according to the specified
 *        parameters in the CAN_FilterInitStruct.
 *
 * @param   CAN_FilterInitStruct - pointer to a CAN_FilterInitTypeDef
 *        structure that contains the configuration information.
 *
 * @return  none
 */
void CAN_FilterInit( CAN_FilterInitTypeDef *CAN_FilterInitStruct )
{
    uint32_t filter_number_bit_pos = 0;

    filter_number_bit_pos = ( ( uint32_t )1 ) << CAN_FilterInitStruct->CAN_FilterNumber;
    CAN1->FCTLR |= FCTLR_FINIT;
    CAN1->FWR &= ~( uint32_t )filter_number_bit_pos;

    if( CAN_FilterInitStruct->CAN_FilterScale == CAN_FilterScale_16bit )
    {
        CAN1->FSCFGR &= ~( uint32_t )filter_number_bit_pos;

        CAN1->sFilterRegister[CAN_FilterInitStruct->CAN_FilterNumber].FR1 =
            ( ( 0x0000FFFF & ( uint32_t )CAN_FilterInitStruct->CAN_FilterMaskIdLow ) << 16 ) |
            ( 0x0000FFFF & ( uint32_t )CAN_FilterInitStruct->CAN_FilterIdLow );

        CAN1->sFilterRegister[CAN_FilterInitStruct->CAN_FilterNumber].FR2 =
            ( ( 0x0000FFFF & ( uint32_t )CAN_FilterInitStruct->CAN_FilterMaskIdHigh ) << 16 ) |
            ( 0x0000FFFF & ( uint32_t )CAN_FilterInitStruct->CAN_FilterIdHigh );
    }

    if( CAN_FilterInitStruct->CAN_FilterScale == CAN_FilterScale_32bit )
    {
        CAN1->FSCFGR |= filter_number_bit_pos;

        CAN1->sFilterRegister[CAN_FilterInitStruct->CAN_FilterNumber].FR1 =
            ( ( 0x0000FFFF & ( uint32_t )CAN_FilterInitStruct->CAN_FilterIdHigh ) << 16 ) |
            ( 0x0000FFFF & ( uint32_t )CAN_FilterInitStruct->CAN_FilterIdLow );

        CAN1->sFilterRegister[CAN_FilterInitStruct->CAN_FilterNumber].FR2 =
            ( ( 0x0000FFFF & ( uint32_t )CAN_FilterInitStruct->CAN_FilterMaskIdHigh ) << 16 ) |
            ( 0x0000FFFF & ( uint32_t )CAN_FilterInitStruct->CAN_FilterMaskIdLow );
    }

#if defined (CH32F20x_D6)
		if(((*(uint32_t *) 0x40022030) & 0x0F000000) == 0)
		{	
				uint32_t i;
			
				for(i = 0; i < 64; i++){
						*(__IO uint16_t *)(0x40006000 + 512 + 4 * i) = *(__IO uint16_t *)(0x40006000 + 768 + 4 * i);
				}	
		}
		
#endif		

    if( CAN_FilterInitStruct->CAN_FilterMode == CAN_FilterMode_IdMask )
    {
        CAN1->FMCFGR &= ~( uint32_t )filter_number_bit_pos;
    }
    else
    {
        CAN1->FMCFGR |= ( uint32_t )filter_number_bit_pos;
    }

    if( CAN_FilterInitStruct->CAN_FilterFIFOAssignment == CAN_Filter_FIFO0 )
    {
        CAN1->FAFIFOR &= ~( uint32_t )filter_number_bit_pos;
    }

    if( CAN_FilterInitStruct->CAN_FilterFIFOAssignment == CAN_Filter_FIFO1 )
    {
        CAN1->FAFIFOR |= ( uint32_t )filter_number_bit_pos;
    }

    if( CAN_FilterInitStruct->CAN_FilterActivation == ENABLE )
    {
        CAN1->FWR |= filter_number_bit_pos;
    }

    CAN1->FCTLR &= ~FCTLR_FINIT;
}

/*********************************************************************
 * @fn      CAN_StructInit
 *
 * @brief   Fills each CAN_InitStruct member with its default value.
 *
 * @param   CAN_InitStruct - pointer to a CAN_InitTypeDef structure which
 *        will be initialized.
 *
 * @return  none
 */
void CAN_StructInit( CAN_InitTypeDef *CAN_InitStruct )
{
    CAN_InitStruct->CAN_TTCM = DISABLE;
    CAN_InitStruct->CAN_ABOM = DISABLE;
    CAN_InitStruct->CAN_AWUM = DISABLE;
    CAN_InitStruct->CAN_NART = DISABLE;
    CAN_InitStruct->CAN_RFLM = DISABLE;
    CAN_InitStruct->CAN_TXFP = DISABLE;
    CAN_InitStruct->CAN_Mode = CAN_Mode_Normal;
    CAN_InitStruct->CAN_SJW = CAN_SJW_1tq;
    CAN_InitStruct->CAN_BS1 = CAN_BS1_4tq;
    CAN_InitStruct->CAN_BS2 = CAN_BS2_3tq;
    CAN_InitStruct->CAN_Prescaler = 1;
}

/*********************************************************************
 * @fn      CAN_SlaveStartBank
 *
 * @brief   This function applies only to CH32 Connectivity line devices.
 *
 * @param   CAN_BankNumber - Select the start slave bank filter from 1..27.
 *
 * @return  none
 */
void CAN_SlaveStartBank( uint8_t CAN_BankNumber )
{
    CAN1->FCTLR |= FCTLR_FINIT;
    CAN1->FCTLR &= ( uint32_t )0xFFFFC0F1 ;
    CAN1->FCTLR |= ( uint32_t )( CAN_BankNumber ) << 8;
    CAN1->FCTLR &= ~FCTLR_FINIT;
}

/*********************************************************************
 * @fn      CAN_DBGFreeze
 *
 * @brief   Enables or disables the DBG Freeze for CAN.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          NewState - ENABLE or DISABLE.
 *
 * @return  none
 */
void CAN_DBGFreeze( CAN_TypeDef *CANx, FunctionalState NewState )
{
    if( NewState != DISABLE )
    {
        CANx->CTLR |= CTLR_DBF;
    }
    else
    {
        CANx->CTLR &= ~CTLR_DBF;
    }
}

/*********************************************************************
 * @fn      CAN_TTComModeCmd
 *
 * @brief   Enables or disabes the CAN Time TriggerOperation communication mode.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          NewState - ENABLE or DISABLE.
 *
 * @return  none
 */
void CAN_TTComModeCmd( CAN_TypeDef *CANx, FunctionalState NewState )
{
    if( NewState != DISABLE )
    {
        CANx->CTLR |= CAN_CTLR_TTCM;

        CANx->sTxMailBox[0].TXMDTR |= ( ( uint32_t )CAN_TXMDT0R_TGT );
        CANx->sTxMailBox[1].TXMDTR |= ( ( uint32_t )CAN_TXMDT1R_TGT );
        CANx->sTxMailBox[2].TXMDTR |= ( ( uint32_t )CAN_TXMDT2R_TGT );
    }
    else
    {
        CANx->CTLR &= ( uint32_t )( ~( uint32_t )CAN_CTLR_TTCM );

        CANx->sTxMailBox[0].TXMDTR &= ( ( uint32_t )~CAN_TXMDT0R_TGT );
        CANx->sTxMailBox[1].TXMDTR &= ( ( uint32_t )~CAN_TXMDT1R_TGT );
        CANx->sTxMailBox[2].TXMDTR &= ( ( uint32_t )~CAN_TXMDT2R_TGT );
    }
}

/*********************************************************************
 * @fn      CAN_Transmit
 *
 * @brief   Initiates the transmission of a message.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          TxMessage - pointer to a structure which contains CAN Id, CAN
 *        DLC and CAN data.
 *
 * @return  transmit_mailbox - The number of the mailbox that is used for
 *        transmission or CAN_TxStatus_NoMailBox if there is no empty mailbox.
 */
uint8_t CAN_Transmit( CAN_TypeDef *CANx, CanTxMsg *TxMessage )
{
    uint8_t transmit_mailbox = 0;

    if( ( CANx->TSTATR & CAN_TSTATR_TME0 ) == CAN_TSTATR_TME0 )
    {
        transmit_mailbox = 0;
    }
    else if( ( CANx->TSTATR & CAN_TSTATR_TME1 ) == CAN_TSTATR_TME1 )
    {
        transmit_mailbox = 1;
    }
    else if( ( CANx->TSTATR & CAN_TSTATR_TME2 ) == CAN_TSTATR_TME2 )
    {
        transmit_mailbox = 2;
    }
    else
    {
        transmit_mailbox = CAN_TxStatus_NoMailBox;
    }

    if( transmit_mailbox != CAN_TxStatus_NoMailBox )
    {
        CANx->sTxMailBox[transmit_mailbox].TXMIR &= TMIDxR_TXRQ;
        if( TxMessage->IDE == CAN_Id_Standard )
        {
            CANx->sTxMailBox[transmit_mailbox].TXMIR |= ( ( TxMessage->StdId << 21 ) | \
                    TxMessage->RTR );
        }
        else
        {
            CANx->sTxMailBox[transmit_mailbox].TXMIR |= ( ( TxMessage->ExtId << 3 ) | \
                    TxMessage->IDE | \
                    TxMessage->RTR );
        }

        TxMessage->DLC &= ( uint8_t )0x0000000F;
        CANx->sTxMailBox[transmit_mailbox].TXMDTR &= ( uint32_t )0xFFFFFFF0;
        CANx->sTxMailBox[transmit_mailbox].TXMDTR |= TxMessage->DLC;

        CANx->sTxMailBox[transmit_mailbox].TXMDLR = ( ( ( uint32_t )TxMessage->Data[3] << 24 ) |
                ( ( uint32_t )TxMessage->Data[2] << 16 ) |
                ( ( uint32_t )TxMessage->Data[1] << 8 ) |
                ( ( uint32_t )TxMessage->Data[0] ) );
        CANx->sTxMailBox[transmit_mailbox].TXMDHR = ( ( ( uint32_t )TxMessage->Data[7] << 24 ) |
                ( ( uint32_t )TxMessage->Data[6] << 16 ) |
                ( ( uint32_t )TxMessage->Data[5] << 8 ) |
                ( ( uint32_t )TxMessage->Data[4] ) );
        CANx->sTxMailBox[transmit_mailbox].TXMIR |= TMIDxR_TXRQ;
    }

    return transmit_mailbox;
}

/*********************************************************************
 * @fn      CAN_TransmitStatus
 *
 * @brief   Checks the transmission of a message.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          TransmitMailbox - the number of the mailbox that is used for
 *        transmission.
 *
 * @return  state -
 *            CAN_TxStatus_Ok.
 *            CAN_TxStatus_Failed.
 */
uint8_t CAN_TransmitStatus( CAN_TypeDef *CANx, uint8_t TransmitMailbox )
{
    uint32_t state = 0;

    switch( TransmitMailbox )
    {
        case( CAN_TXMAILBOX_0 ):
            state =   CANx->TSTATR & ( CAN_TSTATR_RQCP0 | CAN_TSTATR_TXOK0 | CAN_TSTATR_TME0 );
            break;

        case( CAN_TXMAILBOX_1 ):
            state =   CANx->TSTATR & ( CAN_TSTATR_RQCP1 | CAN_TSTATR_TXOK1 | CAN_TSTATR_TME1 );
            break;

        case( CAN_TXMAILBOX_2 ):
            state =   CANx->TSTATR & ( CAN_TSTATR_RQCP2 | CAN_TSTATR_TXOK2 | CAN_TSTATR_TME2 );
            break;

        default:
            state = CAN_TxStatus_Failed;
            break;
    }

    switch( state )
    {
        case( 0x0 ):
            state = CAN_TxStatus_Pending;
            break;

        case( CAN_TSTATR_RQCP0 | CAN_TSTATR_TME0 ):
            state = CAN_TxStatus_Failed;
            break;

        case( CAN_TSTATR_RQCP1 | CAN_TSTATR_TME1 ):
            state = CAN_TxStatus_Failed;
            break;

        case( CAN_TSTATR_RQCP2 | CAN_TSTATR_TME2 ):
            state = CAN_TxStatus_Failed;
            break;

        case( CAN_TSTATR_RQCP0 | CAN_TSTATR_TXOK0 | CAN_TSTATR_TME0 ):
            state = CAN_TxStatus_Ok;
            break;

        case( CAN_TSTATR_RQCP1 | CAN_TSTATR_TXOK1 | CAN_TSTATR_TME1 ):
            state = CAN_TxStatus_Ok;
            break;

        case( CAN_TSTATR_RQCP2 | CAN_TSTATR_TXOK2 | CAN_TSTATR_TME2 ):
            state = CAN_TxStatus_Ok;
            break;

        default:
            state = CAN_TxStatus_Failed;
            break;
    }

    return ( uint8_t ) state;
}

/*********************************************************************
 * @fn      CAN_CancelTransmit
 *
 * @brief   Cancels a transmit request.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          Mailbox -  Mailbox number.
 *            CAN_TXMAILBOX_0.
 *            CAN_TXMAILBOX_1.
 *            CAN_TXMAILBOX_2.
 *
 * @return  none
 */
void CAN_CancelTransmit( CAN_TypeDef *CANx, uint8_t Mailbox )
{
    switch( Mailbox )
    {
        case( CAN_TXMAILBOX_0 ):
            CANx->TSTATR |= CAN_TSTATR_ABRQ0;
            break;

        case( CAN_TXMAILBOX_1 ):
            CANx->TSTATR |= CAN_TSTATR_ABRQ1;
            break;

        case( CAN_TXMAILBOX_2 ):
            CANx->TSTATR |= CAN_TSTATR_ABRQ2;
            break;

        default:
            break;
    }
}

/*********************************************************************
 * @fn      CAN_Receive
 *
 * @brief   Receives a message.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          FIFONumber - Receive FIFO number.
 *            CAN_FIFO0.
 *            CAN_FIFO1.
 *          RxMessage -  pointer to a structure receive message which contains
 *        CAN Id, CAN DLC, CAN datas and FMI number.
 *
 * @return  none
 */
void CAN_Receive( CAN_TypeDef *CANx, uint8_t FIFONumber, CanRxMsg *RxMessage )
{
    RxMessage->IDE = ( uint8_t )0x04 & CANx->sFIFOMailBox[FIFONumber].RXMIR;

    if( RxMessage->IDE == CAN_Id_Standard )
    {
        RxMessage->StdId = ( uint32_t )0x000007FF & ( CANx->sFIFOMailBox[FIFONumber].RXMIR >> 21 );
    }
    else
    {
        RxMessage->ExtId = ( uint32_t )0x1FFFFFFF & ( CANx->sFIFOMailBox[FIFONumber].RXMIR >> 3 );
    }

    RxMessage->RTR = ( uint8_t )0x02 & CANx->sFIFOMailBox[FIFONumber].RXMIR;
    RxMessage->DLC = ( uint8_t )0x0F & CANx->sFIFOMailBox[FIFONumber].RXMDTR;
    RxMessage->FMI = ( uint8_t )0xFF & ( CANx->sFIFOMailBox[FIFONumber].RXMDTR >> 8 );
    RxMessage->Data[0] = ( uint8_t )0xFF & CANx->sFIFOMailBox[FIFONumber].RXMDLR;
    RxMessage->Data[1] = ( uint8_t )0xFF & ( CANx->sFIFOMailBox[FIFONumber].RXMDLR >> 8 );
    RxMessage->Data[2] = ( uint8_t )0xFF & ( CANx->sFIFOMailBox[FIFONumber].RXMDLR >> 16 );
    RxMessage->Data[3] = ( uint8_t )0xFF & ( CANx->sFIFOMailBox[FIFONumber].RXMDLR >> 24 );
    RxMessage->Data[4] = ( uint8_t )0xFF & CANx->sFIFOMailBox[FIFONumber].RXMDHR;
    RxMessage->Data[5] = ( uint8_t )0xFF & ( CANx->sFIFOMailBox[FIFONumber].RXMDHR >> 8 );
    RxMessage->Data[6] = ( uint8_t )0xFF & ( CANx->sFIFOMailBox[FIFONumber].RXMDHR >> 16 );
    RxMessage->Data[7] = ( uint8_t )0xFF & ( CANx->sFIFOMailBox[FIFONumber].RXMDHR >> 24 );

    if( FIFONumber == CAN_FIFO0 )
    {
        CANx->RFIFO0 |= CAN_RFIFO0_RFOM0;
    }
    else
    {
        CANx->RFIFO1 |= CAN_RFIFO1_RFOM1;
    }
}

/*********************************************************************
 * @fn      CAN_FIFORelease
 *
 * @brief   Releases the specified FIFO.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          FIFONumber - Receive FIFO number.
 *            CAN_FIFO0.
 *            CAN_FIFO1.
 *
 * @return  none
 */
void CAN_FIFORelease( CAN_TypeDef *CANx, uint8_t FIFONumber )
{
    if( FIFONumber == CAN_FIFO0 )
    {
        CANx->RFIFO0 |= CAN_RFIFO0_RFOM0;
    }
    else
    {
        CANx->RFIFO1 |= CAN_RFIFO1_RFOM1;
    }
}

/*********************************************************************
 * @fn      CAN_MessagePending
 *
 * @brief   Returns the number of pending messages.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          FIFONumber - Receive FIFO number.
 *            CAN_FIFO0.
 *            CAN_FIFO1.
 *
 * @return  message_pending: which is the number of pending message.
 */
uint8_t CAN_MessagePending( CAN_TypeDef *CANx, uint8_t FIFONumber )
{
    uint8_t message_pending = 0;

    if( FIFONumber == CAN_FIFO0 )
    {
        message_pending = ( uint8_t )( CANx->RFIFO0 & ( uint32_t )0x03 );
    }
    else if( FIFONumber == CAN_FIFO1 )
    {
        message_pending = ( uint8_t )( CANx->RFIFO1 & ( uint32_t )0x03 );
    }
    else
    {
        message_pending = 0;
    }

    return message_pending;
}

/*********************************************************************
 * @fn      CAN_OperatingModeRequest
 *
 * @brief   Select the CAN Operation mode.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          CAN_OperatingMode - CAN Operating Mode.
 *            CAN_OperatingMode_Initialization.
 *            CAN_OperatingMode_Normal.
 *            CAN_OperatingMode_Sleep.
 *
 * @return  status -
 *          CAN_ModeStatus_Failed - CAN failed entering the specific mode.
 *          CAN_ModeStatus_Success - CAN Succeed entering the specific mode.
 */
uint8_t CAN_OperatingModeRequest( CAN_TypeDef *CANx, uint8_t CAN_OperatingMode )
{
    uint8_t status = CAN_ModeStatus_Failed;
    uint32_t timeout = INAK_TIMEOUT;

    if( CAN_OperatingMode == CAN_OperatingMode_Initialization )
    {
        CANx->CTLR = ( uint32_t )( ( CANx->CTLR & ( uint32_t )( ~( uint32_t )CAN_CTLR_SLEEP ) ) | CAN_CTLR_INRQ );

        while( ( ( CANx->STATR & CAN_MODE_MASK ) != CAN_STATR_INAK ) && ( timeout != 0 ) )
        {
            timeout--;
        }
        if( ( CANx->STATR & CAN_MODE_MASK ) != CAN_STATR_INAK )
        {
            status = CAN_ModeStatus_Failed;
        }
        else
        {
            status = CAN_ModeStatus_Success;
        }
    }
    else if( CAN_OperatingMode == CAN_OperatingMode_Normal )
    {
        CANx->CTLR &= ( uint32_t )( ~( CAN_CTLR_SLEEP | CAN_CTLR_INRQ ) );

        while( ( ( CANx->STATR & CAN_MODE_MASK ) != 0 ) && ( timeout != 0 ) )
        {
            timeout--;
        }
        if( ( CANx->STATR & CAN_MODE_MASK ) != 0 )
        {
            status = CAN_ModeStatus_Failed;
        }
        else
        {
            status = CAN_ModeStatus_Success;
        }
    }
    else if( CAN_OperatingMode == CAN_OperatingMode_Sleep )
    {
        CANx->CTLR = ( uint32_t )( ( CANx->CTLR & ( uint32_t )( ~( uint32_t )CAN_CTLR_INRQ ) ) | CAN_CTLR_SLEEP );

        while( ( ( CANx->STATR & CAN_MODE_MASK ) != CAN_STATR_SLAK ) && ( timeout != 0 ) )
        {
            timeout--;
        }
        if( ( CANx->STATR & CAN_MODE_MASK ) != CAN_STATR_SLAK )
        {
            status = CAN_ModeStatus_Failed;
        }
        else
        {
            status = CAN_ModeStatus_Success;
        }
    }
    else
    {
        status = CAN_ModeStatus_Failed;
    }

    return ( uint8_t ) status;
}

/*********************************************************************
 * @fn      CAN_Sleep
 *
 * @brief   Enters the low power mode.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *
 * @return  sleepstatus -
 *            CAN_Sleep_Ok.
 *            CAN_Sleep_Failed.
 */
uint8_t CAN_Sleep( CAN_TypeDef *CANx )
{
    uint8_t sleepstatus = CAN_Sleep_Failed;

    CANx->CTLR = ( ( ( CANx->CTLR ) & ( uint32_t )( ~( uint32_t )CAN_CTLR_INRQ ) ) | CAN_CTLR_SLEEP );

    if( ( CANx->STATR & ( CAN_STATR_SLAK | CAN_STATR_INAK ) ) == CAN_STATR_SLAK )
    {
        sleepstatus =  CAN_Sleep_Ok;
    }

    return ( uint8_t )sleepstatus;
}

/*********************************************************************
 * @fn      CAN_WakeUp
 *
 * @brief   Wakes the CAN up.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *
 * @return  wakeupstatus -
 *            CAN_WakeUp_Ok.
 *            CAN_WakeUp_Failed.
 */
uint8_t CAN_WakeUp( CAN_TypeDef *CANx )
{
    uint32_t wait_slak = SLAK_TIMEOUT;
    uint8_t wakeupstatus = CAN_WakeUp_Failed;

    CANx->CTLR &= ~( uint32_t )CAN_CTLR_SLEEP;

    while( ( ( CANx->STATR & CAN_STATR_SLAK ) == CAN_STATR_SLAK ) && ( wait_slak != 0x00 ) )
    {
        wait_slak--;
    }
    if( ( CANx->STATR & CAN_STATR_SLAK ) != CAN_STATR_SLAK )
    {
        wakeupstatus = CAN_WakeUp_Ok;
    }

    return ( uint8_t )wakeupstatus;
}

/*********************************************************************
 * @fn      CAN_GetLastErrorCode
 *
 * @brief   Returns the CANx's last error code (LEC).
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *
 * @return  errorcode - specifies the Error code.
 *            CAN_ErrorCode_NoErr - No Error.
 *            CAN_ErrorCode_StuffErr - Stuff Error.
 *            CAN_ErrorCode_FormErr - Form Error.
 *            CAN_ErrorCode_ACKErr - Acknowledgment Error.
 *            CAN_ErrorCode_BitRecessiveErr - Bit Recessive Error.
 *            CAN_ErrorCode_BitDominantErr - Bit Dominant Error.
 *            CAN_ErrorCode_CRCErr - CRC Error.
 *            CAN_ErrorCode_SoftwareSetErr - Software Set Error.
 */
uint8_t CAN_GetLastErrorCode( CAN_TypeDef *CANx )
{
    uint8_t errorcode = 0;

    errorcode = ( ( ( uint8_t )CANx->ERRSR ) & ( uint8_t )CAN_ERRSR_LEC );

    return errorcode;
}

/*********************************************************************
 * @fn      CAN_GetReceiveErrorCounter
 *
 * @brief   Returns the CANx Receive Error Counter (REC).
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *
 * @return  counter - CAN Receive Error Counter.
 */
uint8_t CAN_GetReceiveErrorCounter( CAN_TypeDef *CANx )
{
    uint8_t counter = 0;

    counter = ( uint8_t )( ( CANx->ERRSR & CAN_ERRSR_REC ) >> 24 );

    return counter;
}

/*********************************************************************
 * @fn      CAN_GetLSBTransmitErrorCounter
 *
 * @brief   Returns the LSB of the 9-bit CANx Transmit Error Counter(TEC).
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *
 * @return  counter - LSB of the 9-bit CAN Transmit Error Counter.
 */
uint8_t CAN_GetLSBTransmitErrorCounter( CAN_TypeDef *CANx )
{
    uint8_t counter = 0;

    counter = ( uint8_t )( ( CANx->ERRSR & CAN_ERRSR_TEC ) >> 16 );

    return counter;
}

/*********************************************************************
 * @fn      CAN_ITConfig
 *
 * @brief   Enables or disables the specified CANx interrupts.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          CAN_IT - specifies the CAN interrupt sources to be enabled or disabled.
 *            CAN_IT_TME.
 *            CAN_IT_FMP0.
 *            CAN_IT_FF0.
 *            CAN_IT_FOV0.
 *            CAN_IT_FMP1.
 *            CAN_IT_FF1.
 *            CAN_IT_FOV1.
 *            CAN_IT_EWG.
 *            CAN_IT_EPV.
 *            CAN_IT_LEC.
 *            CAN_IT_ERR.
 *            CAN_IT_WKU.
 *            CAN_IT_SLK.
 *          NewState - ENABLE or DISABLE.
 *
 * @return  counter - LSB of the 9-bit CAN Transmit Error Counter.
 */
void CAN_ITConfig( CAN_TypeDef *CANx, uint32_t CAN_IT, FunctionalState NewState )
{
    if( NewState != DISABLE )
    {
        CANx->INTENR |= CAN_IT;
    }
    else
    {
        CANx->INTENR &= ~CAN_IT;
    }
}

/*********************************************************************
 * @fn      CAN_GetFlagStatus
 *
 * @brief   Checks whether the specified CAN flag is set or not.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          CAN_FLAG - specifies the flag to check.
 *            CAN_FLAG_EWG.
 *            CAN_FLAG_EPV.
 *            CAN_FLAG_BOF.
 *            CAN_FLAG_RQCP0.
 *            CAN_FLAG_RQCP1.
 *            CAN_FLAG_RQCP2.
 *            CAN_FLAG_FMP1.
 *            CAN_FLAG_FF1.
 *            CAN_FLAG_FOV1.
 *            CAN_FLAG_FMP0.
 *            CAN_FLAG_FF0.
 *            CAN_FLAG_FOV0.
 *            CAN_FLAG_WKU.
 *            CAN_FLAG_SLAK.
 *            CAN_FLAG_LEC.
 *          NewState - ENABLE or DISABLE.
 *
 * @return  FlagStatus - SET or RESET.
 */
FlagStatus CAN_GetFlagStatus( CAN_TypeDef *CANx, uint32_t CAN_FLAG )
{
    FlagStatus bitstatus = RESET;

    if( ( CAN_FLAG & CAN_FLAGS_ERRSR ) != ( uint32_t )RESET )
    {
        if( ( CANx->ERRSR & ( CAN_FLAG & 0x000FFFFF ) ) != ( uint32_t )RESET )
        {
            bitstatus = SET;
        }
        else
        {
            bitstatus = RESET;
        }
    }
    else if( ( CAN_FLAG & CAN_FLAGS_STATR ) != ( uint32_t )RESET )
    {
        if( ( CANx->STATR & ( CAN_FLAG & 0x000FFFFF ) ) != ( uint32_t )RESET )
        {
            bitstatus = SET;
        }
        else
        {
            bitstatus = RESET;
        }
    }
    else if( ( CAN_FLAG & CAN_FLAGS_TSTATR ) != ( uint32_t )RESET )
    {
        if( ( CANx->TSTATR & ( CAN_FLAG & 0x000FFFFF ) ) != ( uint32_t )RESET )
        {
            bitstatus = SET;
        }
        else
        {
            bitstatus = RESET;
        }
    }
    else if( ( CAN_FLAG & CAN_FLAGS_RFIFO0 ) != ( uint32_t )RESET )
    {
        if( ( CANx->RFIFO0 & ( CAN_FLAG & 0x000FFFFF ) ) != ( uint32_t )RESET )
        {
            bitstatus = SET;
        }
        else
        {
            bitstatus = RESET;
        }
    }
    else
    {
        if( ( uint32_t )( CANx->RFIFO1 & ( CAN_FLAG & 0x000FFFFF ) ) != ( uint32_t )RESET )
        {
            bitstatus = SET;
        }
        else
        {
            bitstatus = RESET;
        }
    }

    return  bitstatus;
}

/*********************************************************************
 * @fn      CAN_ClearFlag
 *
 * @brief   Clears the CAN's pending flags.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          CAN_FLAG - specifies the flag to clear.
 *            CAN_FLAG_RQCP0.
 *            CAN_FLAG_RQCP1.
 *            CAN_FLAG_RQCP2.
 *            CAN_FLAG_FF1.
 *            CAN_FLAG_FOV1.
 *            CAN_FLAG_FF0.
 *            CAN_FLAG_FOV0.
 *            CAN_FLAG_WKU.
 *            CAN_FLAG_SLAK.
 *            CAN_FLAG_LEC.
 *
 * @return  none
 */
void CAN_ClearFlag( CAN_TypeDef *CANx, uint32_t CAN_FLAG )
{
    uint32_t flagtmp = 0;

    if( CAN_FLAG == CAN_FLAG_LEC )
    {
        CANx->ERRSR = ( uint32_t )RESET;
    }
    else
    {
        flagtmp = CAN_FLAG & 0x000FFFFF;

        if( ( CAN_FLAG & CAN_FLAGS_RFIFO0 ) != ( uint32_t )RESET )
        {
            CANx->RFIFO0 = ( uint32_t )( flagtmp );
        }
        else if( ( CAN_FLAG & CAN_FLAGS_RFIFO1 ) != ( uint32_t )RESET )
        {
            CANx->RFIFO1 = ( uint32_t )( flagtmp );
        }
        else if( ( CAN_FLAG & CAN_FLAGS_TSTATR ) != ( uint32_t )RESET )
        {
            CANx->TSTATR = ( uint32_t )( flagtmp );
        }
        else
        {
            CANx->STATR = ( uint32_t )( flagtmp );
        }
    }
}

/*********************************************************************
 * @fn      CAN_GetITStatus
 *
 * @brief   Checks whether the specified CANx interrupt has occurred or not.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          CAN_IT -  specifies the CAN interrupt source to check.
 *            CAN_IT_TME.
 *            CAN_IT_FMP0.
 *            CAN_IT_FF0.
 *            CAN_IT_FOV0.
 *            CAN_IT_FMP1.
 *            CAN_IT_FF1.
 *            CAN_IT_FOV1.
 *            CAN_IT_WKU.
 *            CAN_IT_SLK.
 *            CAN_IT_EWG.
 *            CAN_IT_EPV.
 *            CAN_IT_BOF.
 *            CAN_IT_LEC.
 *            CAN_IT_ERR.
 *
 * @return  ITStatus - SET or RESET.
 */
ITStatus CAN_GetITStatus( CAN_TypeDef *CANx, uint32_t CAN_IT )
{
    ITStatus itstatus = RESET;

    if( ( CANx->INTENR & CAN_IT ) != RESET )
    {
        switch( CAN_IT )
        {
            case CAN_IT_TME:
                itstatus = CheckITStatus( CANx->TSTATR, CAN_TSTATR_RQCP0 | CAN_TSTATR_RQCP1 | CAN_TSTATR_RQCP2 );
                break;

            case CAN_IT_FMP0:
                itstatus = CheckITStatus( CANx->RFIFO0, CAN_RFIFO0_FMP0 );
                break;

            case CAN_IT_FF0:
                itstatus = CheckITStatus( CANx->RFIFO0, CAN_RFIFO0_FULL0 );
                break;

            case CAN_IT_FOV0:
                itstatus = CheckITStatus( CANx->RFIFO0, CAN_RFIFO0_FOVR0 );
                break;

            case CAN_IT_FMP1:
                itstatus = CheckITStatus( CANx->RFIFO1, CAN_RFIFO1_FMP1 );
                break;

            case CAN_IT_FF1:
                itstatus = CheckITStatus( CANx->RFIFO1, CAN_RFIFO1_FULL1 );
                break;

            case CAN_IT_FOV1:
                itstatus = CheckITStatus( CANx->RFIFO1, CAN_RFIFO1_FOVR1 );
                break;

            case CAN_IT_WKU:
                itstatus = CheckITStatus( CANx->STATR, CAN_STATR_WKUI );
                break;

            case CAN_IT_SLK:
                itstatus = CheckITStatus( CANx->STATR, CAN_STATR_SLAKI );
                break;

            case CAN_IT_EWG:
                itstatus = CheckITStatus( CANx->ERRSR, CAN_ERRSR_EWGF );
                break;

            case CAN_IT_EPV:
                itstatus = CheckITStatus( CANx->ERRSR, CAN_ERRSR_EPVF );
                break;

            case CAN_IT_BOF:
                itstatus = CheckITStatus( CANx->ERRSR, CAN_ERRSR_BOFF );
                break;

            case CAN_IT_LEC:
                itstatus = CheckITStatus( CANx->ERRSR, CAN_ERRSR_LEC );
                break;

            case CAN_IT_ERR:
                itstatus = CheckITStatus( CANx->STATR, CAN_STATR_ERRI );
                break;

            default :
                itstatus = RESET;
                break;
        }
    }
    else
    {
        itstatus  = RESET;
    }

    return  itstatus;
}

/*********************************************************************
 * @fn      CAN_ClearITPendingBit
 *
 * @brief   Clears the CANx's interrupt pending bits.
 *
 * @param   CANx - where x can be 1 to select the CAN peripheral.
 *          CAN_IT - specifies the interrupt pending bit to clear.
 *            CAN_IT_TME.
 *            CAN_IT_FF0.
 *            CAN_IT_FOV0.
 *            CAN_IT_FF1.
 *            CAN_IT_FOV1.
 *            CAN_IT_WKU.
 *            CAN_IT_SLK.
 *            CAN_IT_EWG.
 *            CAN_IT_EPV.
 *            CAN_IT_BOF.
 *            CAN_IT_LEC.
 *            CAN_IT_ERR.
 *
 * @return  none
 */
void CAN_ClearITPendingBit( CAN_TypeDef *CANx, uint32_t CAN_IT )
{
    switch( CAN_IT )
    {
        case CAN_IT_TME:
            CANx->TSTATR = CAN_TSTATR_RQCP0 | CAN_TSTATR_RQCP1 | CAN_TSTATR_RQCP2;
            break;

        case CAN_IT_FF0:
            CANx->RFIFO0 = CAN_RFIFO0_FULL0;
            break;

        case CAN_IT_FOV0:
            CANx->RFIFO0 = CAN_RFIFO0_FOVR0;
            break;

        case CAN_IT_FF1:
            CANx->RFIFO1 = CAN_RFIFO1_FULL1;
            break;

        case CAN_IT_FOV1:
            CANx->RFIFO1 = CAN_RFIFO1_FOVR1;
            break;

        case CAN_IT_WKU:
            CANx->STATR = CAN_STATR_WKUI;
            break;

        case CAN_IT_SLK:
            CANx->STATR = CAN_STATR_SLAKI;
            break;

        case CAN_IT_EWG:
            CANx->STATR = CAN_STATR_ERRI;
            break;

        case CAN_IT_EPV:
            CANx->STATR = CAN_STATR_ERRI;
            break;

        case CAN_IT_BOF:
            CANx->STATR = CAN_STATR_ERRI;
            break;

        case CAN_IT_LEC:
            CANx->ERRSR = RESET;
            CANx->STATR = CAN_STATR_ERRI;
            break;

        case CAN_IT_ERR:
            CANx->ERRSR = RESET;
            CANx->STATR = CAN_STATR_ERRI;
            break;

        default :
            break;
    }
}

/*********************************************************************
 * @fn      CheckITStatus
 *
 * @brief   Checks whether the CAN interrupt has occurred or not.
 *
 * @param   CAN_Reg - specifies the CAN interrupt register to check
 *          It_Bit - specifies the interrupt source bit to check.
 *
 * @return  ITStatus - SET or RESET.
 */
static ITStatus CheckITStatus( uint32_t CAN_Reg, uint32_t It_Bit )
{
    ITStatus pendingbitstatus = RESET;

    if( ( CAN_Reg & It_Bit ) != ( uint32_t )RESET )
    {
        pendingbitstatus = SET;
    }
    else
    {
        pendingbitstatus = RESET;
    }

    return pendingbitstatus;
}






